leetCode.86. 分隔链表

题目思路：

代码

class Solution {
public:
    ListNode* partition(ListNode* head, int x) {
        auto lh = new ListNode(-1), rh = new ListNode(-1);
        auto lt = lh, rt = rh;

        for(auto p = head; p; p = p->next ) {
            if(p->val < x) {
                lt = lt->next = p;
            }
            else {
                rt = rt->next = p;
            }
        }

        lt->next = rh->next;
        rt->next = nullptr;

        return lh->next;
    }
};